Problem: $ { \left[\begin{array}{rr}{1} & {0} \\ {-2} & {-1}\end{array}\right]-\left[\begin{array}{rr}{-1} & {1} \\ {3} & {-2}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{1}-{-1} & {0}-{1} \\ {-2}-{3} & {-1}-{-2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{2} & {-1} \\ {-5} & {1}\end{array}\right]}$